1. Field of the Invention
The present invention relates to a motor.
2. Description of the Related Art
In recent years, various components and mechanisms used in a motor vehicle have been developed with specific focus on environmental concerns (e.g., energy efficiency, reduction of carbon dioxide emission, and the like). One of such mechanisms is an “idling stop” mechanism which allows an engine of the vehicle not in motion to stop automatically in order to reduce the carbon dioxide emission.
However, when a compressor is activated by the engine of such vehicle, each time the engine stops, the components activated by the compressor, such as an air conditioner, also stop. In order to prevent such inconvenience, the compressor of the components, such as an air conditioner, is operated by a motor (e.g., IPM (Interior Permanent Magnet)). That is, the compressor is activated by a car battery, which allows the air conditioner or the like to continue to operate even when the engine is not running.
However, a conventional IPM motor has a problem in that magnetic flux leakage may likely to occur via the rotor core thereof at a portion between permanent magnets of opposite magnetic polarity which consequently decreases the efficiency of the motor.
Also, although durability of the rotor core of the IPM motor is a critical issue since a great deal of centrifugal force is applied thereto particularly at the portion in between the permanent magnets, the conventional configuration of the IPM motor including a hollow portion at the rotor core may not fully support such force.